示例php+mysql查询实现无限下级分类树输出

本文实例讲述了php+mysql查询实现无限下级分类树输出。分享给大家供大家参考，具体如下：

这里介绍的php结合mysql查询无限下级树输出，其实就是无限分类。给各位整理了几个php无限分类的例子.

【相关学习推荐：php编程（视频），mysql视频教程】

树输出:

function get_array($user_id,$top=0){global $mysql,$_G;  $sql = "select user_id as name from `{spreads_users}`  where p1.spreads_userid='{$user_id}'";$rows= $mysql->db_fetch_arrays($sql);  if($top==1){  $arr[0]['name']=$user_id;  $arr[0]['children']=array();  }  $top=$top+1;foreach ($rows as $key=>$value) {     $r = get_array($value['name']); //调用函数，传入参数，继续查询下级     $arr[0]['children'][$key]['name']= $value['username']; //组合数组      if(is_array($r)){      $arr[0]['children'][$key]['children']= $r[0]['children'];      }      $i++;    }    return $arr;  }$list = get_array("1000",1); //调用函数1000是顶级IDecho 'var data='.json_encode($list);

这个是输出 Array 然后转让为 json

例子:

表结构:id字段为分类标识，name字段为分类名,father_id字段为所属父分类的id,path字段为分类路径,储存该分类祖先的集合,isdir判断是否是目录,1为是,0为否.

显示函数:

//$count为分类等级sort_list($str,$fatherid,$count){$rs = $this->sql->re_datas("select * from sort where father_id = fatherid");$num = $this->sql->sql_numrows();$i=0;$n = 1;while(isset($rs[$i])){$name = "";for($n = 1 ; $n < $count ; $n ){$name.="│ ";}if($i 1==$num){$name.="└─".$rs[$i][name];}else{$name.="├─".$rs[$i][name];}if($rs[$i][isdir]){$str.="<span style='color:#CCCCCC'>".$name."</span>";}else{$str.=$name";}$temp = $count 1;$str = $this->sort_list($str,$rs[$i][id],$temp);$i ;}return $str;}

其中$this->sql对象为sql操作类对象,re_datas()函数返回查到的数组,sql_numrows()函数返回查询到的数目.

调用方法:

$sort_list = sort_list($sort_list,0,1);

例子:

表:category

id int 主键,自增
name varchar 分类名称
pid int 父类id，默认0

顶级分类的 pid 默认就是0了,当我们想取出某个分类的子分类树的时候,基本思路就是递归,当然,出于效率问题不建议每次递归都查询数据库,通常的做法是先讲所有分类取出来,保存到PHP数组里,再进行处理,最后还可以将结果缓存起来以提高下次请求的效率.
先来构建一个原始数组,这个直接从数据库中拉出来就行:

$categories = array(  array('id'=>1,'name'=>'电脑','pid'=>0),  array('id'=>2,'name'=>'手机','pid'=>0),  array('id'=>3,'name'=>'笔记本','pid'=>1),  array('id'=>4,'name'=>'台式机','pid'=>1),  array('id'=>5,'name'=>'智能机','pid'=>2),  array('id'=>6,'name'=>'功能机','pid'=>2),  array('id'=>7,'name'=>'超级本','pid'=>3),  array('id'=>8,'name'=>'游戏本','pid'=>3),);

目标是将它转化为下面这种结构:

电脑—笔记本——-超级本——-游戏本—台式机手机—智能机—功能机

用数组来表示的话,可以增加一个 children 键来存储它的子分类:

array(  //1对应id，方便直接读取  1 => array(    'id'=>1,    'name'=>'电脑',    'pid'=>0,    children=>array(      &array(        'id'=>3,        'name'=>'笔记本',        'pid'=>1,        'children'=>array(          //此处省略        )      ),      &array(        'id'=>4,        'name'=>'台式机',        'pid'=>1,        'children'=>array(          //此处省略        )      ),    )  ),  //其他分类省略)

处理过程:

$tree = array();//第一步，将分类id作为数组key,并创建children单元foreach($categories as $category){  $tree[$category['id']] = $category;  $tree[$category['id']]['children'] = array();}//第二部，利用引用，将每个分类添加到父类children数组中，这样一次遍历即可形成树形结构。foreach ($tree as $k=>$item) {  if ($item['pid'] != 0) {    $tree[$item['pid']]['children'][] = &$tree[$k];  }}

print_r($tree);打印结果如下:

Array(  [1] => Array    (      [id] => 1      [name] => 电脑      [pid] => 0      [children] => Array        (          [0] => Array            (              [id] => 3              [name] => 笔记本              [pid] => 1              [children] => Array                (                  [0] => Array                    (                      [id] => 7                      [name] => 超级本                      [pid] => 3                      [children] => Array                        (                        )                    )                  [1] => Array                    (                      [id] => 8                      [name] => 游戏本                      [pid] => 3                      [children] => Array                        (                        )                    )                )            )          [1] => Array            (              [id] => 4              [name] => 台式机              [pid] => 1              [children] => Array                (                )            )        )    )  [2] => Array    (      [id] => 2      [name] => 手机      [pid] => 0      [children] => Array        (          [0] => Array            (              [id] => 5              [name] => 智能机              [pid] => 2              [children] => Array                (                )            )          [1] => Array            (              [id] => 6              [name] => 功能机              [pid] => 2              [children] => Array                (                )            )        )    )  [3] => Array    (      [id] => 3      [name] => 笔记本      [pid] => 1      [children] => Array        (          [0] => Array            (              [id] => 7              [name] => 超级本              [pid] => 3              [children] => Array                (                )            )          [1] => Array            (              [id] => 8              [name] => 游戏本              [pid] => 3              [children] => Array                (                )            )        )    )  [4] => Array    (      [id] => 4      [name] => 台式机      [pid] => 1      [children] => Array        (        )    )  [5] => Array    (      [id] => 5      [name] => 智能机      [pid] => 2      [children] => Array        (        )    )  [6] => Array    (      [id] => 6      [name] => 功能机      [pid] => 2      [children] => Array        (        )    )  [7] => Array    (      [id] => 7      [name] => 超级本      [pid] => 3      [children] => Array        (        )    )  [8] => Array    (      [id] => 8      [name] => 游戏本      [pid] => 3      [children] => Array        (        )    ))

优点:关系清楚,修改上下级关系简单.

缺点:使用PHP处理,如果分类数量庞大,效率也会降低.

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